It is well known in the art that various types of treatments of steels can be employed to improve wear resistance, enhancing performance of tribologically stressed steel components, such as those employed in an internal combustion engine. One conventional technique is carbonitriding where the surface of the article becomes enriched with carbon and nitrogen. This process comprises treating the article at elevated temperatures, i.e. about 1550.degree. F. (about 845.degree. C.) to a bout 1700.degree. F. (about 925.degree. C.), with gaseous forms of carbon and nitrogen as is set forth in the ASM Handbook, Volume 4, Heat Treating, p. 376-386, ASM International, 1991 (incorporated herein by reference). Conventionally, when this process is employed, an article is carbonitrided, quenched, tempered, and subsequently net shaped. This process typically produces articles having a surface hardness below HV 750 (Vicker Hardness).
Alternatively, plasa (ion) nitriding has been employed to enrich the article's boundary layer with nitrogen, has been employed. In this process, the hardened layer is formed by using glow discharge in a vacuum vessel where nascent nitrogen impinges on the article through plasma bombardment, forming a compound layer, commonly called a white layer, of predominantly gammna prime nitride (Fe.sub.4 N). (see ASM Handbook, Volume 4, Heat Treating, p.420, ASM International, 1991 (incorporated herein by reference)). When this process is employed, the article is typically treated at lower temperatures than carbonitriding, i.e. about 840.degree. F. (about 450.degree. C.) to about 975.degree. F. (about 525.degree. C.), for an extended period of time which typically reaches or exceeds about twenty-four (24) hours. The layer formed by this process typically has a hardness of HV 700, with greater than HV 1200 in the compound layer.
What is needed in the art is a process for forming wear resistant articles in a reduced processing time.